Rubber hoses of curved shape are required in machine construction, and in most cases in engine construction, in order to conduct liquid from one part of a machine to another in a narrow space. They have the advantage that they are elastic and can therefore also be used in places where the machine parts carry out small relative movements with respect to each other. Such curved hose lengths have their curvature imparted to them prior to vulcanization so that they retain this curvature for their entire life. Generally, curvatures of a considerable angle in a small space are imparted here to the piece of hose.
The manufacture of such curved pieces of hose is effected by producing a strand in an extruder, behind which possibly a textile-thread wrapping machine as well as a second extruder are arranged, the strand being cut into pieces of the required length by means of a cutting device. These cut pieces, after they have been cooled, are placed manually on mandrels and then introduced into a vulcanization unit. Here the lengths of hose are vulcanized on the mandrels, in the position contemplated for them, with the corresponding curvatures. In the manufacture of such curved pieces of hose a large amount of manual work is carried out. This makes these pieces of hose expensive.